Darren, a salesperson at a Carpet & Tile store, tells Larry, a customer, "Buy your flooring here, and I'll install it for less than the store would charge." Larry buys carpeting, which Darren installs for half the store's price, and keeps the money for himself. With respect to the store, Darren has breached

a$.$ the duty of loyalty.

b$.$ the duty of notification.

c$.$ no duty.

d$.$ the duty of performance.